I analyzed patents.tsv looking for gaps in the patent numbers that don't correspond to withdrawn patents. I found 305 patents that must not be in the underlying grant xml files.  Here's a sample that returns no results from the patents endpont while this link finds the same patents at the uspto's site.   

There are also nearly 8,000 patents in the grant xml files and patentsview database which were subsequently withdrawn by the uspto.  Here is a sample from patentsview  and the same patents at uspto.gov